The aim of the proposed work is to isolate and incorporate in the Mueller-Rudin model membrane, the excitable membrane proteins rhodopsin and the acetylcholine receptor and, furthermore, to study in the reconstituted membranes the function, structure and dynamics of the two proteins by fluorescence, chemical and electrophysiological techniques. The unique feature of this work is the use of newly developed techniques of fluorescence spectroscopy (a) to study, independently of function, the incorporation of proteins in the membrane, and (b) to gain insight into conformational correlates of membrane function. More specifically, the aim will be to study (a) permeability changes induced in the model membrane when rhodopsin and the acetylcholine receptor protein are activated by light and acethylcholine, respectively, (b) the molecular topology of the two proteins, (c) the conformational changes which accompany the activation of the acetylcholine receptor and rhodopsin, (d) the possible existence of subunits, their interactions and their effects on function, (e) the interactions of the proteins with specific lipids and the effects of these interactions on membrane permeability. It will also be of interest to synthesize and test, with the synthetic membrane, fluorescent probes which bind to specific sites on the acetylcholine receptor and use these probes to study the receptor in situ by fluorescence microscopy. The undersigned agrees to accept responsibility for the scientific and technical conduct of the project and for provision of required progress reports if a grant is awarded as the result of this application.